Posted
by
Soulskill
on Friday September 16, 2011 @01:07PM
from the you're-gonna-need-a-bigger-boat dept.

RedEaredSlider writes "Researchers at the Massachusetts Institute of Technology are trying to push 3-D printing technology even further. Their goals: create whole working machines and perhaps even buildings. Thus far, 3D printing has been used to make shapes of plastic or metal that can be assembled later. These folks want to change that. One idea is to use concrete in a novel way: 'Not only would it be possible to create fanciful, organic-looking shapes that would be difficult or impossible using molds, but the technique could also allow the properties of the concrete itself to vary continuously, producing structures that are both lighter and stronger than conventional concrete. To illustrate this, Keating uses the example of a palm tree compared to a typical structural column. In a concrete column, the properties of the material are constant, resulting in a very heavy structure. But a palm tree’s trunk varies: denser at the outside and lighter toward the center. As part of his thesis research, he has already made sections of concrete with the same kind of variations of density.'"

The already have. 3d printers can print their own parts, but it requires some manual assembly to make the 2nd printer. I'm sure it's not a very big leap to extend the printer to have an assembly component as well.

Motors I'm not sure about (not sure how the coils get wound, never looked into it). But the ICs are automated in manufacturing, so you could probably add that into the whole setup. It would be difficult but I'd say we're really really close to building a factory factory that produces factory factories.

ICs require a lot of machinery to produce. The cost of a wafer fab is measured in billions of dollars. Even if you start with clean silicon wafers as the input, you've got a lot of work to etch the die and then package it. Every IC requires a lot of complicated setup for that specific chip. We don't have factories that you can just upload a mask to and get a single IC out, we have factories where you set up a mask and then do a production run of a few tens of thousands of chips (at least) because otherw

I suspect that, if made practical on a larger scale, this 3D printing will make variable-property concrete substantially more common, cheap, and swift to put up; but it deserves mention that the Roman architects who constructed the dome of the Pantheon actually used a similar strategy of progressively lighter aggregate mixes as they went further up the dome, resulting in a substantially lighter and more durable structure... A very cute trick that would be handy to see revived.

That "cute trick" needs no revival, it's been used in just about every large scale construction project since well, the Pantheon. This is something wholly different though, since it would allow you to actually vary the density of the concrete within a single application, rather than just stacking progressively lighter applications.

As a kid, I saw an episode of the Jetsons which had a shot of building construction. A large, low profile square box was hoisted into the air and a fully formed building emerged from beneath at about four floors per second. The box must have been one of those printers - and I'm sure someone is going to claim prior art.

If this grad school student were to spend a summer working with concrete, he would learn that it's not a medium suited for 3-D printing.

Civil engineers would reject any concrete structure design proposed with 3-D printing. They despise cold joints, and if a vertical support consisted of dozens of cold joints, that's a no-go from the beginning. That's just one dimension of this flawed concept. Comparing a flexible material like a palm tree to an absolutely rigid material like concrete is pure folly. Concrete structures don't bend under load. They crack and break.

Yup. Concrete can take a beating when you compress it - like in a column. Come and push on that column laterally and watch the whole thing come falling down. It doesn't shear so well. Not an engineer but I've built a few things...

I'm not a metallurgist but I think that print head would have to get pretty nifty to be able to deposit steel one layer at a time but with the same qualities as traditional steel. Making that stuff correctly is tricky business and if done wrong it will just shatter under very small stresses. I'm not saying it can't be done, I just can't imagine how it could be done. Plastic is one thing, but steel is another kettle of fish.

Metals are more suitable for selective laser sintering/melting [wikipedia.org], but I can't fathom how you would combine this with a method where you deposit concrete. I'd expect the concrete to mix with the metal powder and give some sort of unholy porridge-like substance.

I think you missed my point. Wherever I've seen SLM used for metals it involved a large amount of fine powder, parts of which were melted with a laser or some such, hence the name. I was saying that having the powder there for melting would be difficult if not impossible when you have liquid concrete being sprayed into it.

3D printing with metals - that I've seen - isn't like plastics or concrete where you directly deposit the material layer by layer with a nozzle. Instead the feedstock is all around the par

But, why would you want to? There is nothing, and I mean nothing, with the properties of forged steel, except forged steel.

Perhaps if we move manufacturing into space we will get superior materials... like foam steel. And that's not actually superior, except where you want to use it. We could replace most easily replaced structural aluminum extrusions and castings with it to great benefit, for example, and possibly cast iron ones as well.

Point is, whether you're talking about MIM or sintered powder metal, i

Wow you want to make a print head that sprays out a super think layer of steel? They do metal rapid prototyping but they use laser sintering. http://en.wikipedia.org/wiki/Selective_laser_melting [wikipedia.org] Not really the best solution for building indoors.The funny thing is the example they gave. Well we do that now. They are called hollow columns.I do love the idea but it is very iffy.

The University of Michigan in cooperation with the Michigan Department of Transportation trialed some flexible concrete that they made a bridge out of. I forget if it goes over I94 or if it is part of I94. Either way it's a busy bridge. So far as I know it has held up fine. Granted, this is not flexible as in rubber, it's not like you or I could walk up to the bridge and bend it. It flexes when the bridge expands and contracts with the big temperature changes between seasons. Conventional concrete bridge

Maybe you print out the foundation "skin", drop some re-bar in specific locations (that are also printed in place) then have a truck come in later to pour the filling concrete. You avoid having to setup/tear down/transport forms. You can make the foundation any size or shape (again, without special forms) and even color without having to dye the entire batch of concrete. (From what I hear, concrete guys love dyed concrete.../sarcasm)

Obviously this problem would be best served by two cooperating systems. Feedstock would be cement for the concrete extrusion robot. The other feedstock would would be rebar which would be formed by some sort of bending robot.

Actually, there were some videos of pipe bending robots [boingboing.net] that made the rounds on the web recently that make Mr. Rodriquez look like a look like a incompetent toddler. Downright fluid and graceful.

bending-welding-cutting robot. And another robot to come in from under its armpit and weld rebar to rebar. The welding I refer to above is the same as done to train tracks; polish the end of the rebar, butt it up to the next (also polished) piece, and run a bunch of current through them to weld them together.

If you pumped the various constituents of concrete to the head and mixed them there, then sprayed the 'crete over a freshly welded rebar form then you could both reduce waste and eliminate cold joints b

That's pretty much the process that's been proposed by the USC contour crafting group proposed for doing rebar. Print a shell layer, drop in some modular rebar sections,then you fill up the shell with concrete so that your rebar connectors sticks out, and then repeat for the next layer. Another way to do reinforcement is to put a metal coil on your top layer and to print over it, so the coil gets embedded in the concrete. They've actually demonstrated this.

Careful...there are things you can do with concrete which - while quite a bit outside the mainstream of construction - have been used. Naturally, I didn't RTFA, but if the printer can supply an internal web of properly place, ductile material and the concrete can be formed in a continuous process which allows the hydration to occur across the layer interface you could conceivably create some interesting results. It's a long, long way from the 400-800yd cost of concrete today (that's formed, placed, reinforc

actually, there are flexible composite concretes, some that even self-heal if stressed to cracking. And of course maybe 3D printing around support system could allow reinforced concrete printing. We're talking about research for future tech, what an old civil engineer would complain about might have no relevance at all if new materials and methods used. Advancement of civilization is all about new materials and new methods of using them.

They compare concrete columns to palm trees AND BONES... How flexible are bones, again?

If they're healthy, they're more flexible than you might imagine. But then, a lot of things move more than most people imagine, say auto body. Most cars flop all over the place, and the hood or roof can expand by several millimeters due to solar heating alone if your paint is in a dark color. Luckily, the paint expands as well, though when it gets very old and UV-damaged it loses its ability to do so — kind of like when you get old and your bones get calcified.

If there is to be any progress in structure designs then we want to go complex and expensive. And perhaps some technology that is developed for complex and expensive structures may just work their way down also to the cheap and simple designs.

OK, this is all wonderful stuff, I suppose. But surely I'm not the only person who is taken aback by reading the article only to find such titles as "the Media Lab’s Sony Corporation Career Development Assistant Professor of Media Arts and Sciences."

I still haven't got used to stadiums being named after corporations; it's a bit of a shock to see that assistant professors are now so named. Do they have to wear decals?

And the reality is concrete needs rebar to be strong and a support structure to be truly useful.,a href="http://www.shapeways.com/themes/stainless_steel_3dprinting_gallery">These are the only people who have made printed 3D metal, and it has two caveats:

(1) Strong, but not as strong as forged metals.(2) Has to be baked in an oven to transition from powder to solid metal.

So, not really interesting until hey solve the whole in-place metal printing problem. Right now all you can make is trinkets.

Short answer: Nobody wants an all-concrete house. Professor K is a great mechanical engineer, and the concrete printer did what it said on the tin, but at the end of the day it only printed out concrete.

(Source: I was an international rep for Contour Crafting for a while.)

I still think the idea's great - it just needs to be combined with printers/assemblers for other materials in order to not be relegated to a niche market of printing out driveways, ornamental walls, and statues.

a dedicated subset of slashdotters think 3d printing is the salvation of all mankind. its not.
3d printing a building completely disregards the fact that buildings are designed to withstand earthquakes, wind, fire, flood, and a host of other
complex forces that even a cursory glance at your whimsical little makerbot will confirm do not in fact just stop existing because you learned
how to extrude hot plastic and layer it into fun little shapes. things like ventilation, plumbing, and electricity are hard e

If you look at the Contour Crafting [contourcrafting.org] project, it basically prints the wall surfaces using a special concrete. They are used like a formwork and later get filled with standard concrete. You could add other materials like steel cables. As a plus, the printed surface has a very nice finish that you can leave just as it is. You can also print holes right into the wall instead of drilling them afterwards.

I don't think the contour crafting project will ever be built at full scale, but the idea is IMO not doomed fr

the end point of 3D printing is not all-one-piece items. It is intended to be able to create any structures or structures in one "print run" . Being able to create interesting one-piece structures is just a side effect of the building method that is showing to have some interesting potential.

I was thoroughly engaged with my "science and engineering mode" brain active while reading all of this information, that is until Prof. Neri Oxman appeared in the second video and my brain exploded. A quick google images search later and OMFG she's an effing supermodel.

I'm highly disappointed in my scumbag brain for such a base detour from a truly intellectual endeavor.

Did you know that Neanderthals had bigger brains than we do?Do you know why? Because they had a working memory!

"Researchers at the Massachusetts Institute of Technology are trying to push 3-D printing technology even further. Their goals: create whole working machines and perhaps even buildings. Thus far, 3D printing has been used to make shapes of plastic or metal that can be assembled later. "

Also a self-monitoring and repairing capability for the building would be nice.
Although I suppose it would be alarming if you got a message to reboot the building after NEW Building 3.0 was downloaded.

"Thus far, 3D printing has been used to make shapes of plastic or metal that can be assembled later."

This is incorrect. There is at least some 3D printing technology today which makes it possible to print at least basic mechanical parts with no assembly required. Here is a video demonstrating its use, printing a working crescent wrench (including the worm drive for adjusting the size of the grip):http://www.youtube.com/watch?v=ZboxMsSz5Aw [youtube.com]

Amazing, no? That said, the idea of printing out variable-density conc

Okay I live in FL and most homes are concrete here. A lot of block but a growing number are cast.You do not leave bare concrete and you do insulate them. My many of my schools where also CBS and they where not damp or cold.

You frame the inside with cheap, light lumber, with studs placed 2' apart, and then slap some insulation and sheet rock up. Done and done. Now it's actually more comfortable than a timber frame with chip board outer walls and sawdust siding.

The heck with concrete. I'll consider 3D printing tech truly accomplished when they can actually print using layers of silicon and carbon atoms, forming up molecular bonds in lattices and matrices as the structure is built. True, flawless stone reinforced by carbon nanotube meshes sealed by diamond!

While I think 3d printing has some real value and use I don't think this will work out unless there is a major breakthrough in the chemistry of it all.

The fastest curing concrete I know of that has any real strength is the stuff that CalTrans uses to fix big cracks in concrete roadbeds and it takes an hour.

Now the cool thing about the 3rd "printing" of most solids is that the material is in powder form and and a laser is used to fuse small amounts at a time and then build on that until you have the desired

Concrete used to solidify faster, a century or so back. The industry actually changed standard formulations to get a slower-setting concrete because it was solidifying before the workers could get it into place.